1. Field of the Invention
This invention relates to mufflers. More specifically, the invention relates to mufflers of the type comprising a perforated cylinder and containing a metal wool to disperse the impact of sound waves.
2. Description of the Prior Art
In the prior art, there are a large number of compact hollow mufflers adapted to be connected to the exhaust fitting of a diesel air starter, compressor, engine or the like, and to provide a chamber having porous outlet means designed to diffuse the sound waves passing therethrough. Such mufflers, while inexpensive, have been surprisingly effective for their size.
Examples of such prior art mufflers are found in the U.S. Pat. No. 3,380,553, issued Apr. 30, 1968 to S. J. Gibel and U.S. Pat. No. 2,815,088, issued Dec. 3, 1957 to S. J. Gibel.
In the prior art, there has been usage of metal fibers or wool as a medium through which to pass the exhaust gases to diffuse sound associated therewith. The use of such wool is preferred to woven or screen material because it is able to endure longer exhaust cycles than the other forms without "icing up". The use of such wool, however, has presented problems in that the wool invariably needs to be supported and has compacted toward the end of the muffler more remote from the inlet end, leaving a free passage adjacent the inlet end for the exhaust fluid with no sound reduction. A further problem in the use of brass wool has been the provision of adequate means to uniformly distribute the incoming exhaust gas evenly through the full extent of the metal wool extending the length of the muffler.